1. Field of the Invention
The present invention relates to a recording medium best suited for recording with inks and excellent in ink-receiving properties and in the distinctness and other quality of recorded full-color images and to a recording method utilizing the recording medium.
2. Description of the Related Art
The ink-jet recording process comprises ejecting droplets of recording liquid by various techniques (e.g. the electrostatic attraction technique, the technique of providing mechanical vibration or displacement to the recording liquid by using piezoelectric elements, and the technique of heating the recording liquid to produce a foam and utilizing the foaming pressure), and causing parts or all of the droplets to deposit to a recording medium such as paper. This process draws attention as a recording method capable of high speed printing and multicolor printing, with less noise generation.
Aqueous inks are chiefly used as recording liquids for ink-jet recording from the standpoint of safety and recording characteristics, and a polyhydric alcohol or the like is often added to these inks in order to prevent the nozzle clogging and to improve the discharge stability.
Recording media hitherto used for ink-jet recording are ordinary paper and sheets called ink-jet recording papers which are made by forming porous ink-receiving layers on base paper. However, various sophisticated characteristics are increasingly demanded also for recording media with the improvement of ink-jet recorders in functions, such as the speedup of recording and the development of multicolor recording, and with the spreading use of ink-jet recorders. That is, recording medium for ink-jet recording need to satisfy the following fundamental requirements in order to record good quality images with high resolution.
(1) The recording media should absorb ink as rapidly as possible.
(2) When ink dots overlap each other, the recording media should function so that the later applied ink will not diffuse into the previously marked ink dot.
(3) Ink diffusion on the recording media should not be so great as to enlarge the diameter of ink dots more than necessary.
(4) Ink dots on the recording media should have good circularity and the circumferences of the dots should be smooth.
(5) Ink dots on the recording media should exhibit high O.D. (optical density) and the outline of each dot should not be blurred.
In addition, the following requirements need to be satisfied in order to attain such image quality of high resolution by multicolor ink-jet recording as to be comparable to that of color photographs.
(6) The coloring components of ink should be able to develop excellent colors on a recording medium.
(7) The ink-fixing ability of the recording media should be superior since ink droplets as many as the number of ink colors may overlap one another.
No recording medium satisfying all of these requirements has not been known yet.
Most of the conventional recording media for surface image observation purposes are provided with a porous ink-receiving surface layer, the cells of which serve to receive recording liquids and fix the recording agents thereof. Since the recording agents penetrate deep into the ink-receiving layer, the recorded images are low in distinctness.
When the surface of the ink-receiving layer is non-porous, on the contrary, nonvolatile components of ink remain such as polyhydric alcohols on the surface of the layer for many hours after recording thus long times being required for drying and fixing the ink. Therefore, clothes, if brought into contact with the recorded image, will be stained and the image may be impaired.